Hi Alexander, i can't boot the binary kernel here, as the initramfs is included in my kernel, if you send me a patch, i can apply it and test it. Thomas On Tue, 7 Mar 2023 21:54:31 +0100 Alexander Wetzel <alexander@xxxxxxxxxxxxxx> wrote: > >> > > > > I just uploaded a test patch to bugzilla. > > Please have a look if that fixes the issue. > > > > If not I would be interested in the output of your iTXQ status. > > Enable CONFIG_MAC80211_DEBUGFS and run this command when the > > connection is bad and send/share/upload to bugzilla the resulting > > debug.out: > > > > k=1; while [ $k -lt 10 ]; do \ > > cat /sys/kernel/debug/ieee80211/phy?/netdev:*/stations/*/aqm; \ > > k=$(($k+1)); done >> debug.out > > Thomas and I continued with some debugging in > https://bugzilla.kernel.org/show_bug.cgi?id=217119 > > But the results so far are unexpected and we decided to continue the > debugging with the round here. Hoping someone sees something I miss. > > A very summary where we are: > I can't reproduce the bug with a very similar card and kernel config > so far. Thomas card stops the iTXQs for intervalls >30s. Mine > operates normally. > > A more useful but longer summary: > > Thomas updated to a 6.2 kernel and reported "connection drops and > bandwidth problems" with his rt2800usb wlan card. (6.1 is ok.) Asked > for some more details he reported: > "...slow bandwidth stuff works better, but the main problem/test case > is to start a 8-16 mbit video stream, which sometimes runs for a few > seconds and then stops or it doesn't start at all" > > He bisected the issue and identified my commit 4444bc2116ae ("wifi: > mac80211: Proper mark iTXQs for resumption") as culprit. > > Checking the internal iTXQ status when the issue is ongoing shows, > that TID zero is flagged as dirty and thus is not transmitting queued > packets. Interesting line from > /sys/kernel/debug/ieee80211/phy?/netdev:*/stations/*/aqm: > tid ac backlog-bytes backlog-packets new-flows drops marks overlimit > collisions tx-bytes tx-packets flags > 0 2 619736 404 1681 0 0 0 1 4513965 3019 0xe(RUN AMPDU NO-AMSDU DIRTY) > > --> The "normal" iTXQ handling IEEE80211_AC_BE has queued packets and > is flagged as DIRTY. There even is a potential race setting the DIRTY > flag, but the fix for that is not helping. > > Thus Thomas applied two debug patches, to better understand why the > DIRTY flag is not cleared. > > And looking at the output from those we see that the driver stops Tx > by calling ieee80211_stop_queue(). When ieee80211_wake_queue() > mac80211 correctly resumes TX but is getting stopped by the driver > after a single packet again. (The start of the relevant log is > missing, so that may be initially more). > I assume TX is still ok at that stage. But after some singe Tx > operations the driver stops the queues again. Here the relevant part > of the log: > [ 179.584997] XXXX __ieee80211_wake_txqs: waking TID 0 > [ 179.585022] XXXX drv_tx: TX > [ 179.585027] XXXX ieee80211_stop_queue: called > [ 179.585028] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.585030] XXXX __ieee80211_wake_txqs: TID 3 NOT dirty > [ 179.585031] XXXX __ieee80211_wake_txqs: TID 8 NOT dirty > [ 179.585033] XXXX __ieee80211_wake_txqs: TID 11 NOT dirty > [ 179.585034] XXXX __ieee80211_wake_txqs: EXIT > [ 179.585035] XXXX __ieee80211_wake_txqs: ENTRY > [ 179.585036] XXXX __ieee80211_wake_txqs: TID 1 NOT dirty > [ 179.585037] XXXX __ieee80211_wake_txqs: TID 2 NOT dirty > [ 179.585038] XXXX __ieee80211_wake_txqs: TID 9 NOT dirty > [ 179.585040] XXXX __ieee80211_wake_txqs: TID 10 NOT dirty > [ 179.585041] XXXX __ieee80211_wake_txqs: EXIT > [ 179.585047] XXXX drv_tx: TX > [ 179.585056] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.585271] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.585868] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.586120] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.586544] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.586792] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.587317] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.587591] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > [ 179.588569] XXXX ieee80211_tx_dequeue: mark TID 0 dirty. Reason: 1 > .... > [ 214.307617] XXXX ieee80211_wake_queue: called > > > --> So the driver blocked TX for more than 30s. Which is a good > explanation of what Thomas observes. > > But there is nothing mac80211 can do differently here. Whatever is > the real reason for the issue, it's nothing obvious I see. > > Luckily I found a card using the same driver and nearly the same card: > Thomas systems:Linux version 6.2.2-gentoo (root@foo) (gcc (Gentoo > Hardened 12.2.1_p20230121-r1 p10) 12.2.1 20230121, GNU ld (Gentoo > 2.39 p5) 2.39.0) #2 SMP Fri Mar 3 16:59:02 CET 2023ieee80211 phy0: > rt2x00_set_rt: Info - RT chipset 3070, rev 0201 detected > ieee80211 phy0: rt2x00_set_rf: Info - RF chipset 0005 detected > ieee80211 phy0: Selected rate control algorithm 'minstrel_ht' > > My system, using the kernel config from Thomas with only minor > modifications (different filesystems and initramfs settings and > enabled mac80211 debug and developer options): > Linux version 6.2.2-gentoo (root@Perry.mordor) (gcc (Gentoo > 12.2.1_p20230121-r1 p10) 12.2.1 20230121, GNU ld (Gentoo 2.40 p2) > 2.40.0) #2 SMP Tue Mar 7 18:18:47 CET 2023ieee80211 phy0: > rt2x00_set_rt: Info - RT chipset 3070, rev 0200 detected > ieee80211 phy0: rt2x00_set_rf: Info - RF chipset 0005 detected > ieee80211 phy0: Selected rate control algorithm 'minstrel_ht' > ieee80211 phy0: rt2x00lib_request_firmware: Info - Loading firmware > file 'rt2870.bin' > ieee80211 phy0: rt2x00lib_request_firmware: Info - Firmware detected > - version: 0.36 > > But there is one big difference on my system: I can't reproduce the > bug so far. It's working as it should... (I did not apply the debug > patches myself so far) > > I'm now planning to look a bit more into the rt2800usb driver and > provide another debug patch for interesting looking code pieces in it. > > @Thomas: > I've also uploaded you my binary kernel I'm running at the moment > here: https://www.awhome.eu/s/5FjqMS73rtCtSBM > > That kernel should also be able to boot and operate your system. Can > you try that and tell me, if that makes any difference? > > I'm also planning to provide some more debug patches, to figuring out > which part of commit 4444bc2116ae ("wifi: mac80211: Proper mark iTXQs > for resumption") fixes the issue for you. Assuming my understanding > above is correct the patch should not really fix/break anything for > you...With the findings above I would have expected your git bisec to > identify commit a790cc3a4fad ("wifi: mac80211: add wake_tx_queue > callback to drivers") as the first broken commit... > > Alexander
